It is desirable to be able to coat discrete areas of a flexible support in a continuous roll-to-roll manner, to enable the fabrication of flexible electronics, micro lens arrays or display devices, etc. There are a variety of existing techniques based on printing technology, such as flexography, offset and screen printing, currently available to meet this desire, although generally the coating generated by such techniques is not controllable in a way that allows spatial or temporal changes in coating thickness that can be continuously modified.
The use of differential wettability to pattern the support prior to overcoating with the target liquid in a continuous manner—termed continuous discrete coating (CDC)—has been demonstrated in PCT/GB2004/002591. The CDC method allows the use of existing coating hardware to pattern layers but this method relies on a predetermined surface pattern to control the coating thickness and cannot affect coating thickness in a variable way (the coating is either present or absent) nor does the process allow the coating thickness and placement to be continuously controllable. PCT/GB2004/002591 discloses the CDC technique. U.S. Pat. No. 6,368,696 describes a method of depositing multiple layers and subsequently patterning the dried multilayer pack with an additional step, for the manufacture of plasma display panels. JP10337524A discloses a method to manufacture dielectric/electrode panels.
Also desirable is a method to electrically control the movement of small quantities of liquid across a surface. Existing methods employ barriers, airflow, or gravity.
In an electrophotographic modular printing machine of known type, for example, the Eastman Kodak NexPress 2100 printer manufactured by Eastman Kodak, Inc., of Rochester, N.Y., color toner images are made sequentially in a plurality of color imaging modules arranged in tandem, and the toner images are successively electrostatically transferred to a receiver member adhered to a transport web moving through the modules. Commercial machines of this type typically employ intermediate transfer members for the transfer to the receiver member of individual color separation toner images.
Sometimes electrophotographic copiers and printers use a release agent to prevent paper sheets from sticking to the fuser roll after transferred images have been heat fused. Dispensing this oil, typically silicone oil, onto the fuser roller using a blade, roller, or other mechanical means in a controllable manner is complicated by the highly wetting nature of the oil. Oil is only required in image areas (areas containing toner) to affect release of the toner from the heated fuser roller. However oil is typically applied across the entire surface of the fuser roller because there is no means to readily control the application of the oil. Broad application of oil in this manner often causes image artifacts because the oil tends to contaminate sensitive components when the printed media is sent back through the imaging unit to receive an image on the media's rear surface. A means to precisely control the application of highly wetting liquids such as silicone oil is needed. Especially needed is continuous control, both temporally and spatially, of the quantity (or thickness) of such liquids.